An electric stapler, which realizes a large amount of binding processing using a staple magazine in which staple sheets composed of parallel bonded linear metal lines are stacked, is widely used as a stand-alone type stapler or such that it is incorporated in a copying machine or the like. The lower-most layer sheet of the stacked staple sheets inside the staple magazine is fed toward right below a driver by a feed pawl included in the staple feed mechanism of the electric stapler disclosed, e.g., in JP 2005-35151A, and the linear staple of the leading end portion of the lower-most layer sheet is bent formed into a gate shape by a forming plate, is driven by the driver to penetrate through papers, and the leg portion of the staple is bent by a clincher situated on the lower surface side of the papers, whereby the papers are bound.
In the electric stapler using the staple magazine with the linear staple sheets stored therein, since the staple sheets in the lower-most layer inside the staple magazine are fed out sequentially, while the electric stapler is in use, the staple sheet in the lower-most layer is being pulled from the inside of the staple magazine toward the staple guide of the electric stapler. Therefore, in a state where the staple sheet mounts on both the inside of the staple magazine and the staple guide of the electric stapler, the staple magazine cannot be taken out but, when the staple sheets are used up, the staple magazine can be replaced.
As described above, in a case where the staple magazine is replaced when the staple sheets are used up, the staple sheet must be used up during the continuous binding processing and the continuous binding processing must be stopped for replacement of the staple magazine. Also, there is found another problem: that is, even when it is previously known that the number of the staple sheets remaining in the staple magazine is small, an operator must start the binding operation and wait for the time of the replacement of the staple magazine.